earth, moon, and sun

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1 Earth, Moon, and Sun S8.D.3.1.1-3

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Earth, Moon, and Sun. S8.D.3.1.1-3. Earth’s 2 Motions. Great Site. 2. Revolution (orbit) – go around the Sun. Rotation – Spin (rotate) on its axis. Rotation. The turning of a planet on its axis. 23.5 0. Axis. Axis: - PowerPoint PPT Presentation

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Page 1: Earth, Moon, and Sun

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Earth, Moon, and Sun

S8.D.3.1.1-3

Page 2: Earth, Moon, and Sun

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Earth’s 2 Motions

1.Rotation

– Spin (rotate) on its axis

2. Revolution (orbit)

– go around the Sun

Great Site

Page 3: Earth, Moon, and Sun

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Rotation• The turning of a planet on its

axis

• We have days and nights because of Earth rotating in and out of sunlight

•Axis:–Imaginary line that runs from the North Pole, through the center of Earth, to the South Pole.–Earth’s axis is tilted at 23.5 0

Axis23.5 0

Table of Planets day

Page 4: Earth, Moon, and Sun

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Rotation• The direction of Earth’s

rotation is counterclockwise (when looking from above the North Pole)

• Because Earth rotates counterclockwise, it appears the Sun rises in the East and sets in the West

Page 5: Earth, Moon, and Sun

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Rotation• It takes Earth 24 hrs to complete one

rotation

• One complete rotation of any planet is called a Day

• At the Equator, Earth rotates 1,000 mph

• The faster a planet rotates, the shorter the day is on that planet

Cool Fact: Earth is slowing down at a rate of 0.0018 seconds per century

Page 6: Earth, Moon, and Sun

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Revolution• Movement of a planet around the Sun• Counterclockwise (from above NP)• One complete revolution of any planet

around the Sun is called a year• Earth rotates 365 ¼ times during one

revolution around the Sun (There are 365 ¼ days in a year)

We make up for that extra ¼ day by adding a day to our calendar (Feb 29th) every 4 years Leap Year

Page 7: Earth, Moon, and Sun

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Revolution

• The closer a planet is to the Sun, the shorter its year is , because:

1. It has to travel a shorter distance

2. Its speed is greater due to the Sun’s gravity

**Earth Revolves at an average of 67,000 mph

Page 8: Earth, Moon, and Sun

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Revolution• Orbit - The path a planet follows around the

Sun

- Shape is elliptical (Oval) with the Sun off-center (not in the middle!)

91 million miles95 million miles

Average= 93 million miles

Perihelion

Page 9: Earth, Moon, and Sun

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2 Forces that Keep Earth in Orbit:

1. Inertia(A) Body in motion will remain in motion

(B) Body at rest will remain at rest

**Inertia is why the planets keep moving ( in a straight line)

Unless acted upon by an outside force

2. Gravity• The Sun’s gravity pull planets toward the Sun and

keeps them in their orbital path

Page 10: Earth, Moon, and Sun

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Tropic of Cancer

Equator

Equator

Tropic of Capricorn~9hrs

~12 hrs

~15hrs

~12 hrs

Page 11: Earth, Moon, and Sun

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24 hrs daylight

24 hrs daylight

24 hrs darkness

24 hrs darkness

Why is there More Hrs of Daylight in Summer?

Page 12: Earth, Moon, and Sun

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Seasons• The seasons in one hemisphere are

opposite of the seasons in the other Hemisphere

**Seasons in the Southern Hemisphere are more extreme than in the Northern Hemisphere

Page 13: Earth, Moon, and Sun

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Tropic of Capricorn (23.50 below Equator)

Tropic of Cancer (23.50 above Equator)

Equator

Northern Hemisphere

Southern Hemisphere

Bill Nye- seasons

Page 14: Earth, Moon, and Sun

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Seasons Animations:

• http://projects.astro.illinois.edu/data/Seasons/seasons.html

• http://esminfo.prenhall.com/science/geoanimations/animations/01_EarthSun_E2.html

• http://astro.unl.edu/naap/motion1/animations/seasons_ecliptic.html

Video clipVideo clip #2

Bill Nye Seasons

Page 15: Earth, Moon, and Sun

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The Moon• Revolves around Earth

• ¼ Earth’s diameter (2,159 miles)

• 1/6 of Earth’s gravity

• Frozen water ice at the poles (in deep shadowed craters)

• Mainly rock and dust (brought back 840lbs of rock to Earth

Page 16: Earth, Moon, and Sun

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The MoonNO atmosphere therefore NO weather

•Temp range is large since it lacks an atmosphere

250F = high during the day-250F = low at night

• Lots of craters from impacts because it lacks an atmosphere

•Old and unchanged because it lacks an atmosphere

Page 17: Earth, Moon, and Sun

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Our Moon Has 2 Motions:

1. Rotation• counterclockwise• 10.7 mph on its axis (6.70)• Takes 28 days to rotate once • Lunar Day = 28 Earth days

2. Revolution• counterclockwise• Around Earth at 2,300 mph• Orbit is Tilted (5º)• Orbit is elliptical (Perigee and apogee)• Average distance to the moon is 238,000 miles• Lunar Year = 28 Earth days

A Day is as long as a Year on the Moon!

Page 18: Earth, Moon, and Sun

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Why Don’t We See the Far Side?

• The Moon rotates 1 time around its axis as it makes 1 revolution around Earth.

• It finishes a rotation at the same time it finishes a revolution

• Period of Rotation = Period of Revolution28 Earth Days Dark

Side

FACT:

The Moon does not rotate and revolve at the same speed!

Page 19: Earth, Moon, and Sun

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Phases of the Moon

• The Moon reflects sunlight

• It does NOT produce its own light

• We see different phases (shapes) depending on where the moon is in its orbit

• It takes the Moon about 28 Earth days to complete one revolution around Earth and go through all of its phases

Page 20: Earth, Moon, and Sun

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New Moon

• During a New Moon we can’t see the moon from Earth

• The side hit by sunlight is facing AWAY from Earth

• Occurs when the Moon passes between the Earth and Sun

Moon is above or below Earth’s plane

Page 21: Earth, Moon, and Sun

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Full Moon

• After a New Moon, the Moon continues to revolve in a counterclockwise direction allowing us to see more and more of the side facing us. (Waxing Phases)

• When it gets halfway around Earth, we see ALL of the side facing us

Page 22: Earth, Moon, and Sun

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Full Moon (cont.)

• Earth is between the Moon and Sun

Moon is above or below Earth’s plane

•As the Moon continues to revolve from a full moon position, we see less and less of the side facing us (Waning Phases), until we have another New Moon

Page 23: Earth, Moon, and Sun

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Animation Animation

Page 24: Earth, Moon, and Sun

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Eclipses1. Lunar Eclipse

• Moon is being eclipsed (blocked from our sight)

2. Solar Eclipse• Sun is being eclipsed by the moon (blocked from

our sight)• Moon is 400 x smaller than the Sun• Moon can perfectly block out sun because the

moon is 400x closer to us than the sun is

•Earth is 4x bigger than Moon

•Sun is 100x bigger than Earth

FACTS:

Page 25: Earth, Moon, and Sun

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Lunar Eclipse• Earth is directly between the Sun and a Full Moon

(all 3 bodies are in line)• Moon is in the shadow of Earth (no sunlight hitting it)

• Only happens 2-4 times a year (not all total)

Whole back side of Earth can see Lunar Eclipse

Zone of partial shadow

Zone of complete shadow

Page 26: Earth, Moon, and Sun

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Page 27: Earth, Moon, and Sun

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Page 28: Earth, Moon, and Sun

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Solar Eclipse• When a New Moon is directly between the Earth

and Sun (all 3 bodies are in line)• Sunlight is blocked (by the moon) from reaching a

small area of Earth, so only people living in that area see the solar eclipse

• At least 2 a year (not all total)

People in penumbra see partial solar

People in umbra see total solar

Page 29: Earth, Moon, and Sun

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Page 30: Earth, Moon, and Sun

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Tides• Rising and falling water levels

of our oceans• Moon’s and Sun’s gravity

makes water bulge out on Earth• The Moon’s gravity has a

greater effect because it’s closer than the Sun

• The area aligned with the moon High Tide

• The area not aligned with the moon Low Tide

Neap tides

Spring tides

Bill Nye- Moon